Torsion coil spring

ABSTRACT

A spring suitable for use in bedding construction, including mattresses, mattress-bases and the like which is able to achieve a variety of spring heights and resiliences using the same thickness of wire. The spring includes a first leg ( 2 ), a first upper foot ( 3 ), a first lower foot ( 4 ), a second leg ( 2 ), a second upper foot ( 3 ), a second lower foot ( 4 ), at least one coil spring ( 5 ) and linking means ( 6 ). The spring&#39;s first leg links the first upper foot to the first lower foot and includes at least one coil spring ( 5 ) at some point along its length. The spring&#39;s second leg links the second upper foot to the second lower foot and includes at least one coil ( 5 ) spring at some point along its length. The linking means links the first upper foot to the second upper foot in such a way that the first leg, first upper foot, and first lower foot are oriented at approximately 180 degrees relative to the second leg, second upper foot, and second lower foot.

BACKGROUND

The present invention relates to improvements in spring construction,and especially to bedding springs for use in mattress and/or mattressbase construction, or the like.

PRIOR ART

Numerous forms of bedding springs are known according to the prior art.However, many examples of springs according to the prior art giveunsatisfactory performance, are not adaptable for alternativelight-/medium-/heavy-duty bedding construction and/or for alternativebudget or premium markets. In many cases, completely different types ofsprings are specified for different types of bedding/mattressconstruction and/or for different priced market sectors.

Some forms of prior art bedding springs are not conducive to economicalmass production and/or are not suitable for economical bedding ormattress construction. The bedding manufacturing industry is verycompetitive and very cost sensitive.

A further disadvantage of known bedding springs are that in order toachieve different spring heights or resilience levels, differentthicknesses of spring wire must be used. Having to change from one typeof wire to another increases manufacture time and cost.

OBJECTS OF THE PRESENT INVENTION

It is an object of the present invention to provide an improved form ofspring suitable for use in bedding manufacture which overcomes or at theleast minimises the prior art problems referred to above.

It is a further object of this invention to provide an improved form ofspring suitable for use in bedding construction which at the very leastprovides consumers and bedding manufacturers with an alternative choiceto prior art spring and bedding manufacture.

It is an additional object of this invention to provide an improved formof spring suitable for use in bedding construction which is able toachieve a variety of spring resiliences using the same thickness ofwire.

It is a further object of this invention to provide an improved form ofspring suitable for use in bedding construction which is suitable foruse with a variety of thicknesses of mattress using the same thicknessof wire.

It is another object of this invention to provide a bedding spring ofvariable construction to satisfy the variable requirements of the marketas to end product function and/or quality.

It is vet a further object of this invention to provide mattresses,mattress-bases and other forms of bedding or the like which includesprings of the form as herein described in their construction.

These and other objects of the invention will be apparent from thefollowing further but non-limiting, disclosure of the invention.

THE INVENTION

According to one aspect of the present invention, there is provided aspring suitable for use in bedding construction, including mattresses,mattress-bases and the like, which in front elevation has a nominalinverted-U construction or profile with two depending spaced-apart legportions joined together at their upper end by a bight portion which inplan view extends diagonally from the front edge of one said leg portionto the rear edge of the adjacent or other leg portion, wherein the onesaid leg portion in end elevation has generally M-shaped (or W-shaped)profile rotated through 90° and said other leg portion has a generallyM-shaped (or W-shaped) profile rotated through 90° but in the oppositedirection to the direction of rotation of the first or one said legportion, wherein said spring is of unitary or contiguous construction,and wherein each said leg portion includes at least one coil spring inits construction, preferably located at one or more bight portions ofthe M- or W-profile, and wherein each coil spring may comprise one or aplurality of coils.

According to another aspect of the present invention, there is provideda mattress, mattress-base or other form of bedding or the like having aframe which includes a plurality of springs of the above type in itsconstruction.

According to a further aspect of the present invention there is providea spring suitable for use in bedding construction, including mattresses,mattress-bases and the like including at least one leg, at least oneupper foot, at least one lower foot and at least one coil spring whereinsaid at least one leg links said at least one upper foot to said atleast one lower foot and includes said at least one coil spring at somepoint along its length.

Preferably said at least one coil spring has an axis of rotation whichis substantially perpendicular to the plane of orientation of said atleast one leg.

Preferably said at least one coil spring includes at least one 360degree turn.

Preferably said at least one coil spring is located at the junctionbetween said at least one leg and said at least one upper foot.

Preferably said at least one coil spring is located at the junctionbetween said at least one leg and said at least one lower foot.

Preferably said at least one coil spring is located on said at least oneleg at a point substantially midway between the upper foot and the lowerfoot.

Preferably said at least one leg has a profile including at least onepeak or trough.

Preferably said at least one leg has a profile including a series ofpeaks and troughs.

Preferably said series of peaks and troughs forms a generally zig-zagshaped profile.

Preferably said at least one leg includes at least one coil springlocated at one or more of the peaks or troughs.

Preferably said at least one leg has one peak or trough and has agenerally V-shaped (or U-shaped) profile.

Preferably said at least one leg includes one coil spring located at thepeak or trough of its V-shaped (or U-shaped) profile.

Preferably said at least one leg includes a first coil spring located atthe junction between said at least one leg and said at least one upperfoot and a second coil spring located at the junction between said atleast one leg and said at least one lower foot.

Preferably including a third coil spring located at the peak or troughof said at least one leg.

Preferably said at least one upper foot includes at least one kink atsome point-along its length to prevent movement of said spring whenfixed to a body of a mattress.

Preferably said at least one lower foot includes at least one kink atits free end to prevent movement of said spring, when fixed to a mainframing of a mattress.

According to a further aspect of the present invention there is provideda spring substantially as described here including a first leg, a firstupper foot, a first lower foot, a second leg, a second upper foot, asecond lower foot, at least one coil spring and linking means whereinsaid first leg links said first upper foot to said first lower foot andincludes at least one coil spring at some point along its length, andwherein said second lea links said second upper foot to said secondlower foot and includes at least one coil spring at some point along itslength, and wherein said linking means links said first upper foot tosaid second upper foot.

Preferably said first leg, first upper foot, and first: lower foot havesubstantially the same shape as said second leg, second upper foot, andsecond lower foot.

Preferably said linking means links a toe of said first upper foot to atoe of said second upper foot.

Preferably said linking means links the toe of said first upper foot tothe toe of said second upper foot so that said first leg, first upperfoot, and first lower foot are oriented at approximately 180 degreesrelative to said second leg, second upper foot, and second lower foot.

Preferably said linking means extends substantially diagonally from thetoe of said first upper foot to the toe of said second upper foot.

Preferably said spring is of unitary or contiguous construction.

Preferably said spring is made from a single piece of wire or similarmaterial.

The present invention will now be described in more detail according tothree preferred but non-limiting embodiments and with reference to theaccompanying

FIG. 1: Is a perspective view of the first preferred embodiment of thepresent invention

FIG. 2: Is a front elevation view of the first preferred embodiment ofthe present invention

FIG. 3: Is a rear elevational view of the first preferred embodiment ofthe present invention;

FIG. 4: Is a side elevational view of the first preferred embodiment ofthe present invention;

FIG. 5: Is a top view of the first preferred embodiment of the present

FIG. 6: Is a bottom view of the first preferred embodiment of thepresent invention;

FIG. 7: Is a perspective view of the second preferred embodiment of thepresent invention;

FIG. 8: Is a front elevational view of the second preferred embodimentof the present invention;

FIG. 9: Is a rear elevational view of the second preferred embodiment ofthe present invention;

FIG. 10: Is a side elevational view of the second preferred embodimentof the present invention;

FIG. 11: Is a top view of the second preferred embodiment of the presentinvention;

FIG. 12: Is a bottom view of the second preferred embodiment of thepresent invention;

FIG. 13: Is a perspective view of the third preferred embodiment of thepresent invention;

FIG. 14: Is a front elevational view of the third preferred embodimentof the present invention;

FIG. 15: Is a rear elevational view of the third preferred embodiment ofthe present invention;

FIG. 16: Is a side elevational view of the third preferred embodiment ofthe present invention;

FIG. 17: Is a top view of the third preferred embodiment of the presentinvention;

FIG. 18: Is a bottom view of the third preferred embodiment of thepresent invention;

FIRST PREFERRED EMBODIMENT (FIGS. 1 TO 6)

As can be seen in FIGS. 1 to 6 the first preferred embodiment of thespring 1 of the present invention includes two legs 2, two upper feet 3,two lower feet 4, two coils 5, a link 6, two kinks 7 and two bends 8.The return portion or “kink” 7 on the end of both lower feet 4 ispresent to prevent the bottom portion of the spring 1 from slipping outof the ties and/or fixings used to fasten the spring to the main framingof the mattress (not shown). The length and angle of the return or“kink” 7 are variable depending on the ties and/or fixings used. In somecases, where a return portion or kink 7 is not required, the wire wouldbe straight, without a “kink 7”.

The radius 9 at the bottom and top of both legs 2 prevents stressconcentrations at these points when the spring 1 is compressed and canbe varied according to the degree of flexibility required in the spring1 as a whole.

The diameter of the coil 5, which would usually, but not always, besituated in the middle of the overall height, is varied to achieve astiffer or softer spring as required for individual applications. Asmaller diameter would result in a stiffer spring 1, while a largerdiameter would give a softer spring 1. If an extremely soft spring 1 isrequired, two or even three turn coils 5 could be used instead of thesingle turn coils 5 illustrated.

Similar in application to the kinks 7, the bends 8 at the extremities ofthe lower feet 4 are used to prevent movement of the top pan of thespring 1 when fixed to the body of a mattress (not shown). The width,depth and position of these bends 8 would also be determined by the tiesand/or fixing,s used to fasten the spring 1 to the main framing of themattress (not shown). With some methods of fixing it would not benecessary to have a bend 8, and the wire would be left straight.

Radii 9 avoid stress concentrations at points where the wire is bent.Ideally these radii 9 should be as large as possible while stillallowing for the spring 1 to be secured to the mattress frame (notshown).

The overall length of the spring form 1 determines the number ofsupports in the mattress frame per unit length. A shorter overall lengthwould allow more spring forms 1 to be used providing for a strongermattress. A longer overall length would result in fewer spring forms 1being used, resulting in a softer mattress. The overall design of themattress frame would also dictate the overall length required.

The overall width of the spring form 1 has a bearing on the stiffness ofthe spring 1 as a whole. A narrow spring 1 would be relatively stiff,while a wider spring 1 would be softer. The overall design of themattress frame would also dictate the overall width required.

The overall height of the spring form 1 is determined by the thicknessof the mattress to which it is being, fitted. The overall height alsohas a bearing, on the overall stiffness of the spring 1. A spring form 1with a greater height would be stiffer than a spring With a shorterheight.

SECOND PREFERRED EMBODIMENT (FIGS. 7 to 13)

As can be seen in FIGS. 7 to 13 the second preferred embodiment of thespring 1 of the present invention includes two legs 2, two upper feet 3,two lower feet 4, four coils 5, a link 6, two kinks 7 and two bends 8.The return portion or “kink” 7 on the end of both lower feet 4 ispresent to prevent the bottom portion of the spring 1 from slipping outof the ties and/or fixings used to fasten the spring to the main framingof the mattress (not shown). The length and angle of the return or kink7 are variable depending on the ties and/or fixings used. In some cases,where a return portion or kink 7 is not required, the wire would bestraight, without a “kink 7”.

The diameter of the coils 5 is varied to achieve a stiffer or softerspring 1 as required for individual applications. A smaller diameterwould result in a stiffer spring 1, while a larger diameter would give asofter spring 1. If an extremely soft spring 1 is required, two or eventhree turn coils 5 could be used instead of the single turn coils 5illustrated.

The radii 9, which would usually, but not always, be situated in themiddle of the overall heights, prevent stress concentrations at thesepoints when the spring 1 is compressed and can be varied according tothe degree of flexibility required in the spring 1.

Similar in application to the kinks 7, the bends 8 at the extremities ofthe lower feet 4 are used to prevent movement of the top part of thespring 1 when fixed to the body of a mattress (not shown). The width,depth and position of these bends 8 would also be determined by the tiesand/or fixings used to fasten the spring 1 to the main framing of themattress (not shown). With some methods of fixing it would not benecessary to have a bend 8, and the wire would be left straight.

Radii 9 avoid stress concentrations at points where the wire is bent.Ideally these radii 9 should be as large as possible while stillallowing for the spring 1 to be secured to the mattress frame (notshown).

The overall length of the spring form 1 determines the number ofsupports in the mattress frame per unit length. A shorter overall lengthwould allow more spring forms 1 to be used providing for a strongermattress. A longer overall length would result in fewer spring forms 1being used, resulting in a softer mattress. The overall design of themattress frame would also dictate the overall length required.

The overall width of the spring form 1 has a bearing on the stiffness ofthe spring 1 as a whole. A narrow spring 1 would be relatively stiff,while a wider spring 1 would be softer. The overall design of themattress frame would also dictate the overall width required. Theoverall height of the spring form 1 is determined by the thickness ofthe mattress to which it is being fitted. The overall height also has abearing on the overall stiffness of the spring 1. A spring form 1 with agreater height would be stiffer than a spring with a shorter height.

THIRD PREFERRED EMBODIMENT (FIGS. 13 to 18)

As can be seen in FIGS. 13 to 18 the third preferred embodiment of thespring 1 of the present invention includes two legs 2, two upper feet 3,two lower feet 4, six coils 5, a link 6, two kinks 7 and two bends 8.The return portion or “kink”7 on the end of both lower feet 4 is presentto prevent the bottom portion of the spring 1 from slipping out of theties and/or fixings used to fasten the spring to the main framing of themattress (not shown). The length and angle of the return or kink 7 arevariable depending on the ties and/or fixings used. In some cases, wherea return portion or kink 7 is not required, the wire would be straight,without a “kink 7”.

The diameter of the coils 5 is varied to achieve a stiffer or softerspring 1 as required for individual applications. A smaller diameterwould result in a stiffer spring 1, while a larger diameter would give asofter spring 1. If an extremely soft spring 1 is required, two or eventhree turn coils 5 could be used instead of the single turn coils 5illustrated.

The radius 9 at the bottom and top of both legs 2 prevents stressconcentrations at these points when the spring 1 is compressed and canbe varied according to the degree of flexibility required in the spring1 as a whole.

Similar in application to the kinks 7, the bends 8 at the extremities ofthe lower feet 4 are used to prevent movement of the top part of thespring 1 when fixed to the body of a mattress (not shown). The width,depth and position of these bends 8 would also be determined by the tiesand/or fixings used to fasten the spring 1 to the main framing of themattress (not shown). With some methods of fixing it would not benecessary to have a bend 8, and the wire would be left straight.

Radii 9 avoid stress concentrations at points where the wire is bent,ideally these radii 9 should be as large as possible while stillallowing for the spring 1 to be secured to the mattress frame (notshown).

The overall length of the spring form 1 determines the number ofsupports in the mattress frame per unit length. A shorter overall lengthwould allow more spring forms 1 to be used providing for a strongermattress. A longer overall length would result in fewer spring forms 1being used, resulting in a softer mattress. The overall design of themattress frame would also dictate the overall length required.

The overall width of the spring form 1 has a bearing on the stiffness ofthe spring 1 as a whole. A narrow spring 1 would be relatively stiff,while a wider spring 1 would be softer. The overall design of themattress frame would also dictate the overall width required.

The overall height of the spring form 1 is determined by the thicknessof the mattress to which it is being fitted. The overall height also hasa bearing on the overall stiffness of the spring 1. A spring form 1 witha greater height would be stiffer than a spring with a shorter height.

Springs according to the present invention are fabricated from suitablewire grades known in the art to spring and bedding manufacturers.Similarly bedding utilising such springs is manufactured according totechniques known to bedding manufacturers.

Although the invention has been described with reference to examples anddrawings relating to preferred embodiments of the invention, it will beappreciated by persons to whom this specification is addressed that theinvention is not limited thereto or thereby, and that alternatives toand modifications of specifically described features may be made orincluded without departing from the spirit or scope of the invention asdisclosed herein. All such alternatives and modifications are therebyintended to be included as part of this invention.

What is claimed is:
 1. A spring suitable for use in beddingconstruction, said spring including a first leg, a first upper foot, afirst lower foot, wherein said first leg, first upper foot and firstlower foot are substantially coplanar said spring further including asecond leg, a second upper foot, and a second lower foot wherein saidsecond leg, second upper foot and second lower foot are substantiallycoplanar, wherein said first leg links said first upper foot to saidlower foot and includes at least one coil spring at some point along itslength; wherein said second leg links said second upper foot to saidsecond lower foot and includes at least one coil spring at some pointalong its length; wherein a linking means links said first upper foot tosaid second upper foot and extends transversely from said first upperfoot and said second upper foot; wherein the junction between the firstupper foot and the first leg is defined by either a single bend radiuslying substantially in the plane of the first leg, or a single coil; andwherein the junction between the second upper foot and the second leg isdefined by either a single bend radius lying substantially in the planeof the second leg, or a single coil.
 2. The spring as claimed in claim 1wherein said first leg, first upper foot, and first lower foot havesubstantially the same shape as said second leg, second upper foot, andsecond lower foot.
 3. The spring as claimed in either of claims 1 or 2wherein said linking means links a toe of said first upper foot to a toeof said second upper foot.
 4. The spring as claimed in claim 3 whereinsaid linking means links the toe of said first upper foot to the toe ofsaid second upper foot so that said first leg, first upper foot, andfirst lower foot are oriented at approximately 180 degrees relative tosaid second leg, second upper foot, and second lower foot.
 5. The springas claimed in claim 3 wherein said linking means extends substantiallydiagonally from the toe of said first upper foot to the toe of saidsecond upper foot.
 6. The spring as claimed in claim 1 wherein said atleast one coil spring has an axis of rotation which is substantiallyperpendicular to the plane of orientation of the first or second legwhich it is situated on.
 7. The spring as claimed in claim 6 whereinsaid at least one coil spring includes at least one 360 degree turn. 8.The spring as claimed in claim 1 wherein said at least one coil springis located at the junction between said first leg and said first upperfoot.
 9. The spring as claimed in claim 1 wherein said at least one coilspring is located at the junction between said second leg and saidsecond upper foot.
 10. The spring as claimed in claim 1 wherein said atleast one coil spring is located at the junction between said first legand said first lower foot.
 11. The spring as claimed in claim 1 whereinsaid at least one coil spring is located at the junction between saidsecond leg and said second lower foot.
 12. The spring as claimed inclaim 1 wherein said at least one coil spring is located on said firstleg at a point substantially midway between the first upper foot and thefirst lower foot.
 13. The spring as claimed in claim 1 wherein said atleast one coil spring is located on said second leg at a pointsubstantially midway between the second upper foot and the second lowerfoot.
 14. The spring as claimed in claim 1 wherein said first leg has aprofile including at least one peak or trough.
 15. The spring as claimedin claim 1 wherein said second leg has a profile including at least onepeak or trough.
 16. The spring as claimed in claim 14 wherein said firstleg has a profile including a series of peaks or troughs.
 17. The springas claimed in claim 14 wherein said second leg has a profile including aseries of peaks and troughs.
 18. The spring as claimed in either ofclaim 16 or 17 wherein said series of peaks and troughs forms agenerally zig-zag shaped profile.
 19. The spring as claimed in claim 16wherein said first leg includes at least one coil spring located at oneor more of the peaks or troughs.
 20. The spring as claimed in claim 16wherein said second leg includes at least one coil spring located at oneor more of the peaks or troughs.
 21. The spring as claimed in claim 14wherein said first leg has one peak or trough and has a generallyV-shaped or U-shaped profile.
 22. The spring as claimed in claim 14wherein said second leg has one peak or trough and has a generallyV-shaped or U-shaped profile.
 23. The spring as claimed in claim 21wherein said first leg includes one coil spring located at the peak ortrough of its V-shaped or U-shaped profile.
 24. The spring as claimed inclaim 22 wherein said second leg includes one coil spring located at thepeak or trough of its V-shaped or U-shaped profile.
 25. The spring asclaimed in claim 1 wherein said first leg includes a first coil springlocated at the junction between said first leg and said first upper footand a second coil spring located at the junction between said first legand said first lower foot, and wherein said second leg includes a thirdcoil spring located at the junction between said second leg and saidsecond upper foot and a fourth coil spring located at the junctionbetween said second leg and said second lower foot.
 26. The spring asclaimed in claim 25 further including a fifth coil spring located at thepeak or trough of said first leg and a sixth coil spring located at thepeak or trough of said second leg.
 27. The spring as claimed in claim 1wherein said first upper foot includes at least one kink at some pointalong its length to prevent movement of said spring when fixed to a bodyof a mattress.
 28. The spring as claimed in claim 1 wherein said secondupper foot includes at least one kink at some point along its length toprevent movement of said spring when fixed to a body of a mattress. 29.The spring as claimed in claim 1 wherein said first lower foot includesat least one kink at its free end to prevent movement of said springwhen fixed to a main framing of a mattress.
 30. The spring as claimed inclaim 1 wherein said second lower foot includes at least one kink at itsfree end to prevent movement of said spring when fixed to a main framingof a mattress.
 31. The spring as claimed in claim 1 wherein said springis of unitary or contiguous construction.
 32. The spring as claimed inclaim 31 wherein said spring is made from a single piece of wire orsimilar material.
 33. The spring as claimed in claim 1 wherein the firstupper foot extends toward the second leg at an acute angle from thefirst leg as measured along the second leg and wherein the second upperfoot extends toward the first leg at an acute angle from the second legas measured along the first leg.